Automatic fire alarm switch



y 6, 1950 c. A. HOLZMACHER 2,507,715

' AUTOMATIC FIRE ALARM SWITCH Filed Oct. 29, 1946 2 Sheets-Sheet 2 BATI'E RY Q) mmvzroxfl CHARL ES 4. HOLZMACHE/Q A T TOR/V5 V Patented May 16, 1950 UNITED STATES PATENT OFFICE AUTOMATIC FIRE ALARM SWITCH Charles A. Holzmacher, Middle Village, N. Y.

Application October 29, 1946, Serial No. 706,377

3 Claims. 1

This invention relates to an improved temperature responsive circuit closer for fire alarm circuits, and is primarily intended for home and building installation and use, to increase the security of the occupants and users of the home or building.

One of the objects of the invention is the provision of a circuit closer which will remain normally inactive, during normal room temperatures, but which will become immediately active when the room temperature rises above normal, as the result of a fire, and which will close an alarm circuit, so as to signal the room, home or building occupants of the existence of the danger arising from the fire.

With the above and other objects in View the,

structions, combinations and arrangements of,

parts, clearly described in the following specification, and fully illustrated in the drawings, in which- Fig. 1 is a side view of one form of the invention.

Fig. 2 is a vertical sectional view, taken on line 2-2 of Fig. 1, looking in the direction of the arrows.

Fig. 3 is a side view of another form of the invention.

Fig. 4 is a front elevation thereof, partly in section.

Fig. 5 is a side elevation of another form of the circuit closer.

Fig. 6 is a front elevation thereof.

Fig. 7 is a perspective view of another form of the circuit closer.

Fig. 8 is a similar view of still another form of the circuit closer.

Fig. 9 is a diagrammatic view of a circuit including a series of individual room circuit closers and a common alarm bell or signal device, operated by a battery supply.

Referring to the drawings which illustrate the practical embodiment of the invention, 5 designates a base wall plate and 6 a complementary housing box, which is mounted on the flange 1 of the base plate 5.

The base plate 5 is formed with a struck-out lug or bracket flange 8, on which the lower end of a hair-pin type of spring 9 is mounted by means of the screw Ill. The spring 9 is provided with spring arms II and I2, each of which is formed with sinuous bends l3. The two spring arms are restrained toward each other by means of the meltable link M, which normally prevents the spring arms from moving outwardly.

On one side of the flange 1 a metal contact plate I 5 is secured against the insulation l6, and the plate 15 is connected by the screw lEa to the circuit line wire ll. On the other side of the flange i a contact plate 18 is secured against the insulation l9, and is connected to the circuit wire 26 by the screw I8a.

When the temperature of the room in which the unit is installed rises above normal, as the result of a fire, the meltable link [4 will be melted and the spring arms H and I2 will spring outwardly to establish contact with the plates l5 and 13, thereby allowing the electrical current to flow from the wire I! to the wire 20, and operate the signal connected in circuit therewith.

In Figs. 3 and 4, I show another form of the circuit closer, wherein the wall or base plate 25 is provided with a struck out lug or flange 26, from which the meltable rod 27 is suspended. Directly beneath this rod and spaced well below it a cup 28 of non-conductive material is supported on the struck out lug or flange 29. On one side of this cup the electrical contact 39 is secured, and to this contact the circuit wire 3| is connected, and on the other side of the cup the electrical contact 32 is secured, and to this contact the line or circuit 33 is secured.

When the room temperature rises above normal as the result of a fire the rod 2'! will melt and drop into the cup 28, and provide a molten mass which will establish electrical connection between the internal contacts 30 and 32, thus closing the circuit of the alarm connected with the closer.

In Figs. 5 and 6, I show another form of the invention, wherein the wall or base plate 33 is provided with a struck-out lug 34, on which the hair pin spring 35 is mounted by means of the screw or fastener 36. The spring arms 31 and 38 of this spring are held toward each other by means of the trigger 39, which is pivoted to the base plate 33 by the pin 43. The trigger 39 is provided with a pendant arm 41 which is connected to the upper end of the thermostatic metal strip 42, and the lower end of this strip is connected to the lug 34. The trigger is also provided with a short lateral arm 43, which is bifurcated to receive the spring arms 31 and 38, and thus hold these arms toward each other under normal room temperatures, for release when a higher temperature causes the thermostatic metal strip 42 to expand and to rock the arm 4| of the trigger to release position, by turning on its pivot, so that the spring arms will be allowed to move outwardly, and to engage the electrical contacts 43 and 44, thereby closing the alarm circuit.

In Fig. '7 I show another form of the circuit closer, comprising the thermostatic base 59, consisting of two metal strips having different temperature coefficient, and the cross strip which is provided with a loop 52 to receive the base strip 50. The base strip is secured in position by means of fasteners extended through the terminal holes 5911 and 59b, and when expansionat high temperatures takes place one of the strips of the base 50 expands more than the other the ends of the cross strip M will be displaced to establish contact with circuit contacts.

In Fig. 8 I show another form of the invention, wherein a composite thermostatic baseconsisting of two strips having difierent tempera-ture c0eflicient 55 is engaged by the cam 56 on the shaft 51. When the strip E5, which is secured by the angu-' lar end 55a, is heated one strip of the base 55 willexpand more than the: other a-ndthereby establish electrical contact with terminals (not shown).

In-Fig. 9 I show a series of similar thermostatic circuit olosersfifi, each having one terminal 61a connected toa common circuit wire of an alarm circuit at 62, and another terminal Bib connected to the other wire 69 ofthe circuit. The wire 62 is connected to-the supply battery 54, which is connected with the signal or alarm bell 65', andthis bell is connected with the other wire 63. When anyone of the closers 6i! responds-to the influence of fire heat the alarm circuit will be closed and the bell or signal'will' be actuated.

It is understood that various changes may be made in the construction of the details, their combination and arrangement, and the installation of the units, within the scope of the claims which herein define the invention.

Having described the invention, I-claim as-new:

1. A temperatureresponsive circuit closer for fire'alarm devices comprising a base plate having a struck-out lug, a hairpin type contact spring having its closed lower end supported on said lug, means securing the spring to said lug, the spring arms having sinuous bends, the bends of the arms opposing one another at difierent elevations thereon, the lowermost opposing bends being spaced from one another, the uppermost opposing bends adjoining one another, a housing fitted on said base, contacts depending from; the upper end of the housing and terminals'secured to the contacts and through the housing to support the contacts, the uppermost opposing bends of said spring arms being adapted to engage the contacts when made free from one another, and temperature responsive means engageable with the uppermost means securing the spring to said ing, the spring arms having sinuous bends, the bends of the arms opposing one another at different elevations thereon, the lowermost opposing bends being spaced from one another, the uppermost opposing bends adjoining one another, a housing fitted on said base, contacts depending from the upper end of the housing and terminals secured to the contacts and through the housing to support the contacts, theuppermost, opposing bends of said spring armsbeingadapted-to engage the'contacts when made free from one another, and temperature responsive means engageable with the uppermost. opposing bends of said spring arms to normally restrain them from contact with the electrical contacts of: the housing, and said temperature responsive means comprising meltable material disposed between the uppermost opposing bend'si of I the spring arms and connecting the spring arms together in closed relationship with respect to one another. 7

3. A temperature responsive circuit closer for fire alarm devices comprising a base plate having a struck-out lug, ahairpin type contact spring havinglits closed lower end supported on said lug, means securing the spring to saidlug, the spring arms having sinuous bends, the bends of the arms opposing one another at different elevations thereon, the lowermost opposing bendsbeing spaced from one another, the uppermost opposing bends adjoining one another, ahousing fitted on said base, contacts depending from the upper end of the housing and, terminals secured to the contacts and through the housing to support the contacts, the uppermost opposing bends of said spring arms being adapted to engage the contacts when made free from one another, and temperature responsive means engageable with the uppermost opposing bends of said spring arms to normally restrain them from'contact with the electrical contacts of the housing, and said temperature responsive means comprising a thermostatic metal strip connected to the lower end of the base and protruding upwardly, a trigger pivotally connected to the housing and having bifurcated portions engageable with the uppermost opposing bends of saidspring arms to restrain them against outward movement, said trigger having a depending arm connected with the thermostatic metal strip.

CHARLES A. I-IO-LZMACHER.

REFERENCES CITED The following references are of record in. the file of this patent:

UNITED STATES PATENTS Number Name Date 760,281 Trull May 17, 1904 821,581 Bean et al May 22, 1906 939,128 Goodchild Nov. 2, 1909 1,124,410 Franck Jan. 12, 1915 1,139,486 Caldwell May 18, 1915 1,264,868 Carlson Apr. 30, 1918 2,402,312 Burch June 18, 1946 

